Fix: EADDRINUSE address already in use :::3000 on Windows

node:events:486
      throw er; // Unhandled 'error' event
      ^
Error: listen EADDRINUSE: address already in use :::3000
    at Server.setupListenHandle [as _listen2] (node:net:1948:16)
    at listenInCluster (node:net:2005:12)
    at Server.listen (node:net:2110:7)

The fix

Another process is already listening on the port. Find its process ID (PID), stop it, then start your server again.

PowerShell:

Get-NetTCPConnection -LocalPort 3000 -State Listen | Select-Object OwningProcess
Stop-Process -Id <PID> -Force

Command Prompt:

netstat -ano | findstr :3000
taskkill /PID <PID> /F

In netstat, the PID is the last number on the LISTENING line:

TCP    0.0.0.0:3000    0.0.0.0:0    LISTENING    11156

Check what you’re about to stop

The PID might be a dev server from another project that you still need. Look before you stop it:

Get-Process -Id <PID>

Or just use another port

Most dev servers accept a port flag or a PORT environment variable:

npx next dev -p 3001
npx vite --port 5174

For your own Node server, read the port from the environment so it’s easy to change:

const port = Number(process.env.PORT) || 3000;
server.listen(port);

Why it happens

Only one process can listen on a given port at a time. The usual culprits:

• a dev server still running in another terminal tab or editor window
• a server from a crashed or closed session that’s still running in the background
• two projects that both default to port 3000

What didn’t work